The present disclosure relates to a semiconductor device and a manufacturing method, and particularly to a semiconductor device configured by attaching two substrates in a state in which electrodes are electrically joined to each other and a manufacturing method thereof.
Thus far, two-dimensionally structured semiconductor devices have been highly integrated by introducing fine processes and improving mounting density, but there is a physical limitation in highly integrating two-dimensional structures using the above-described method. Therefore, three-dimensionally structured semiconductor devices have been developed to further decrease the size of semiconductor devices and further increase the density of pixels. For example, a three-dimensionally structured semiconductor device obtained by stacking a sensor substrate having photoelectric conversion portions and a circuit substrates having peripheral circuit portions and attaching both substrates together is proposed in Japanese Unexamined Patent Application Publication No. 2006-191081.
The above-described three-dimensionally structured semiconductor device is produced by using two substrates having an attaching surface on which a Cu electrode and an insulating film are exposed, aligning the Cu electrodes in a state in which the attaching surfaces face each other, and, furthermore, thermally treating the Cu electrodes, thereby attaching the substrates together. As described above, there are three-dimensionally structured semiconductor devices obtained by stacking and attaching substrates together through direct joining of the Cu electrodes (Cu—Cu junction) (for example, refer to Japanese Unexamined Patent Application Publication No. 2000-299379, Japanese Unexamined Patent Application Publication No. 2006-522461, Japanese Unexamined Patent Application Publication No. 2010-129576, and Japanese Unexamined Patent Application Publication No. 2012-256736)